Patent GB-700681-A (GB)
Title: Improvements relating to continuous horizontal rotary filters
IPC: B01D33/82
Filed: 1950-09-26
Abstract: 700,681. Filters. INDUSTRIAL & FINANCIAL ASSOCIATION, Inc. Sept. 26, 1950 [Oct. 26, 1,949], No. 23546/50. Class 46 A. continuous horizontal filter with rocking cells movable round a circular or other closed path comprises filter cells of light construction each having a wall and a substantially flat impervious bottom, assembled by peripheral flanges with the interposed edges of a perforated bed of resilient material supporting a filter cloth, spacing means being provided between the bed and the cell bottom, and the latter having a filtrate opening spaced from the rocking axis of the cell. Filter cells 1, Fig. 2, are each mounted on a hollow shaft 3 for rotation in bearings 4, 5 secured to a framework 6 which is carried by wheels 7, 8 on rails 9, 10, and is moved in a horizontal circular path by pinions 12 (one not shown) driven by a motor 14 through reduction gearing 15 and engaging a rack 13 on the framework 6. Each cell 1 comprises a flat bottom plate 22, Fig. 7, an intermediate perforated and studded member 23 preferably of rubber and a flanged wall 24 all secured together and to an angleiron framework 2, Fig. 5, by bolts 25. A filter cloth 30 is held by rods 31 in slots 29 at the inner and outer edges of the support 23. Each cell is drained from one comer into a flexible pipe 41 preferably of armoured rubber led through the hollow shaft 3, Fig. 5, on which the framework 2 is mounted and through the inner bearing 4 to a branch 52, Fig. 14, of the rotating crown 51 of a central distributer 43. The crown 51 includes axial openings 67, one for each filter cell, and has secured to its underside a bronze ring 72 for centring it with respect to a fixed column 70. A fixed crown 68 on which the crown 51 rotates has seven peripheral slots substantially in alignment with seven similar slots in the top of an annular box 69. These slots communicate with seven compartments into which the box 69 is divided by partitions; one of these compartments is open to the atmosphere, while each of the other six is connected to a vacuum separator 46, Fig. 2, by an opening 85 and a pipe 45. The crown, 51 is rotated by a framework 60, 61, Fig. 24, which engages a square head 55, Fig. 14, and is free to slide along guides 59 on members 58 secured to a ring 57. The ring 57 is in turn rotated by the framework 6 to which it is connected by radial, arms 56, Fig. 2. The hollow shaft 3 of each cell has secured at its outer end a cranked lever 17, Fig. 2, whose arms carry two rollers 18, 19, one before and one behind the rocking axis, running on tracks 20, 21 which are horizontal tor the greater part of their path to retain the filter cell 1 . in a horizontal position during charging, filtration and part of the washing steps. Where the cell is in communication with the atmosphere through the appropriate compartment of the box 69 the tracks 20, 21 are formed so that for a short distance the cell is tilted at 45 degrees, is then inverted and is finally restored to a horizontal position. The cake is discharged and the cell sluiced by liquid from sprays disposed both above and below the cell at this stage. The filtrate space in the cell is subjected to the normal vacuum of, eg., 300 to 400 mm. of water, between discharge of the cake and recharging, in order to dry it. The cell is charged with liquid to be filtered from a shoot 38 depending from a runway 39 (not shown) and fed by a pipe 40. In alternative forms of the filter cells the filtrate spacing may be provided by a member with an upper face undulating in a direction transverse to the rocking axis and interposed between the bottom and a flat perforated filter-medium-supporting member, or by transverse undulations of the bottom itself, the channels formed by the undulations ending in a lateral collector channel leading to'the filtrate discharge opening. Specification 700,740 is referred to.